.\"	$NetBSD: statfs.2,v 1.10 1995/06/29 11:40:48 cgd Exp $
.\"
.\" Copyright (c) 1989, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"	@(#)statfs.2	8.3 (Berkeley) 2/11/94
.\"
.Dd August 14, 2008
.Dt STATFS 2
.Os
.Sh NAME
.Nm statfs,
.Nm statfs64,
.Nm fstatfs,
.Nm fstatfs64
.Nd get file system statistics
.Sh SYNOPSIS
.Fd #include <sys/param.h>
.Fd #include <sys/mount.h>
.Ft int
.Fn statfs "const char *path" "struct statfs *buf"
.Ft int
.Fn fstatfs "int fd" "struct statfs *buf"
.Sh TRANSITIONAL SYNOPSIS (NOW DEPRECATED)
.Ft int
.br
.Fn statfs64 "const char *path" "struct statfs64 *buf" ;
.sp
.Ft int
.br
.Fn fstatfs64 "int fd" "struct statfs64 *buf" ;
.Sh DESCRIPTION
The
.Fn statfs
routine returns information about a mounted file system.
The
.Fa path
argument is the path name of any file or directory within the mounted file system.
The
.Fa buf
argument is a pointer to a 
.Fa statfs
structure.
When the macro
.Dv _DARWIN_FEATURE_64_BIT_INODE
is not defined (see
.Xr stat 2
for more information on this macro), the
.Fa statfs
structure is defined as:
.Bd -literal
typedef struct { int32_t val[2]; } fsid_t;

#define MFSNAMELEN      15 /* length of fs type name, not inc. nul */
#define MNAMELEN        90 /* length of buffer for returned name */

struct statfs { /* when _DARWIN_FEATURE_64_BIT_INODE is NOT defined */
    short   f_otype;	/* type of file system (reserved: zero) */
    short   f_oflags;	/* copy of mount flags (reserved: zero) */
    long    f_bsize;	/* fundamental file system block size */
    long    f_iosize;	/* optimal transfer block size */
    long    f_blocks;	/* total data blocks in file system */
    long    f_bfree;	/* free blocks in fs */
    long    f_bavail;	/* free blocks avail to non-superuser */
    long    f_files;	/* total file nodes in file system */
    long    f_ffree;	/* free file nodes in fs */
    fsid_t  f_fsid;	/* file system id */
    uid_t   f_owner;	/* user that mounted the file system */
    short   f_reserved1;	/* reserved for future use */
    short   f_type;	/* type of file system (reserved) */
    long    f_flags;	/* copy of mount flags */
    long    f_reserved2[2];	/* reserved for future use */
    char    f_fstypename[MFSNAMELEN]; /* fs type name */
    char    f_mntonname[MNAMELEN];    /* directory on which mounted */
    char    f_mntfromname[MNAMELEN];  /* mounted file system */
    char    f_reserved3;	/* reserved for future use */
    long    f_reserved4[4];	/* reserved for future use */
};
.Ed
.Pp
However, when the macro
.Dv _DARWIN_FEATURE_64_BIT_INODE
is defined, the
.Fa statfs
structure is defined as:
.Bd -literal
#define MFSTYPENAMELEN  16 /* length of fs type name including null */
#define MAXPATHLEN      1024	
#define MNAMELEN        MAXPATHLEN

struct statfs { /* when _DARWIN_FEATURE_64_BIT_INODE is defined */
    uint32_t    f_bsize;        /* fundamental file system block size */ 
    int32_t     f_iosize;       /* optimal transfer block size */ 
    uint64_t    f_blocks;       /* total data blocks in file system */ 
    uint64_t    f_bfree;        /* free blocks in fs */ 
    uint64_t    f_bavail;       /* free blocks avail to non-superuser */ 
    uint64_t    f_files;        /* total file nodes in file system */ 
    uint64_t    f_ffree;        /* free file nodes in fs */ 
    fsid_t      f_fsid;         /* file system id */ 
    uid_t       f_owner;        /* user that mounted the filesystem */ 
    uint32_t    f_type;         /* type of filesystem */ 
    uint32_t    f_flags;        /* copy of mount exported flags */ 
    uint32_t    f_fssubtype;    /* fs sub-type (flavor) */ 
    char        f_fstypename[MFSTYPENAMELEN];   /* fs type name */ 
    char        f_mntonname[MAXPATHLEN];        /* directory on which mounted */ 
    char        f_mntfromname[MAXPATHLEN];      /* mounted filesystem */ 
    uint32_t    f_reserved[8];  /* For future use */ 
};
.Ed
.Pp
Note that the
.Fa f_fstypename ,
.Fa f_mntonname ,
and
.Fa f_mntfromname
fields are also wider in this variant.
.Pp
Fields that are undefined for a particular file system are set to -1.
The
.Fn fstatfs
routine returns the same information about an open file referenced by descriptor
.Fa fd .
.Sh FLAGS
.Bl -tag -width MNT_UNKNOWNPERMISSIONS
These are some of the flags that may be present in the f_flags field. 
.It Dv MNT_RDONLY
A read-only filesystem
.It Dv MNT_SYNCHRONOUS
File system is written to synchronously
.It Dv MNT_NOEXEC
Can't exec from filesystem
.It Dv MNT_NOSUID
Setuid bits are not honored on this filesystem
.It Dv MNT_NODEV
Don't interpret special files
.It Dv MNT_UNION
Union with underlying filesysten
.It Dv MNT_ASYNC
File system written to asynchronously
.It Dv MNT_EXPORTED
File system is exported
.It Dv MNT_LOCAL
File system is stored locally
.It Dv MNT_QUOTA
Quotas are enabled on this file system
.It Dv MNT_ROOTFS
This file system is the root of the file system
.It Dv MNT_DOVOLFS
File system supports volfs
.It Dv MNT_DONTBROWSE
File system is not appropriate path to user data
.It Dv MNT_UNKNOWNPERMISSIONS
VFS will ignore ownership information on filesystem objects
.It Dv MNT_AUTOMOUNTED
File system was mounted by automounter
.It Dv MNT_JOURNALED
File system is journaled
.It Dv MNT_DEFWRITE
File system should defer writes
.It Dv MNT_MULTILABEL
MAC support for individual labels
.It Dv MNT_CPROTECT
File system supports per-file encrypted data protection
.El
.Sh CAVEATS
In Mac OS X versions before 10.4, f_iosize is 4096. On these older
systems, use MAXBSIZE instead.
.Sh RETURN VALUES
Upon successful completion, a value of 0 is returned.
Otherwise, -1 is returned and the global variable
.Va errno
is set to indicate the error.
.Sh ERRORS
The
.Fn statfs
routine fails if one or more of the following are true:
.Bl -tag -width Er
.It Bq Er ENOTDIR
A component of the path prefix of
.Fa Path
is not a directory.
.It Bq Er ENAMETOOLONG
The length of a component of
.Fa path
exceeds 
.Dv {NAME_MAX}
characters, or the length of
.Fa path
exceeds 
.Dv {PATH_MAX}
characters.
.It Bq Er ENOENT
The file or directory referred to by
.Fa path
does not exist.
.It Bq Er EACCES
Search permission is denied for a component of the path prefix of
.Fa path .
.It Bq Er ELOOP
Too many symbolic links were encountered in translating
.Fa path .
.It Bq Er EFAULT
.Fa Buf
or
.Fa path
points to an invalid address.
.It Bq Er EIO
An
.Tn I/O
error occurred while reading from or writing to the file system.
.El
.Pp
The
.Fn fstatfs
routine fails if one or more of the following are true:
.Bl -tag -width Er
.It Bq Er EBADF
.Fa fd
is not a valid open file descriptor.
.It Bq Er EFAULT
.Fa Buf
points to an invalid address.
.It Bq Er EIO
An
.Tn I/O
error occurred while reading from or writing to the file system.
.El
.Sh TRANSITIONAL DESCRIPTION (NOW DEPRECATED)
The
.Fa statfs64
and
.Fa fstatfs64
routines are equivalent to their corresponding non-64-suffixed routine,
when 64-bit inodes are in effect.
They were added before there was support for the symbol variants, and so are
now deprecated.
Instead of using these, set the
.Dv _DARWIN_USE_64_BIT_INODE
macro before including header files to force 64-bit inode support.
.Pp
The
.Fa statfs64
structure used by these deprecated routines is the same as the
.Fa statfs
structure when 64-bit inodes are in effect (see above).
.Sh SEE ALSO
.Xr stat 2 ,
.Xr getfsstat 2
.Sh HISTORY
The
.Fn statfs
function first appeared in 4.4BSD. The
.Fn statfs64
and 
.Fn fstatfs64
first appeared in Max OS X 10.5 (Leopard) and are now deprecated
in favor of the corresponding symbol variants.
